LG UltraGear 27GX790A-B / MSI MPG 321URX QD-OLED

LG UltraGear 27GX790A-B: 27-inch class (26.5-inch) QHD 480 Hz OLED

MSI MPG 321URX QD-OLED: MPG 321URX QD-OLED, black. The DisplayPort 2.1 MPG 322URX QD-OLED and the white MPG 321URXW are separate models.

SpecificationLG UltraGear 27GX790A-BMSI MPG 321URX QD-OLED
Release year20252024
Model27GX790A-B (US version 27GX790A-B.AUS)

LG’s US spec sheet carries a 2024 copyright; LG Brazil lists the model as a 2025 product.

LG		—
Panel26.5-inch (27-inch class) OLED, 16:9

The actual viewable diagonal is 26.5 inches.

LG		31.5-inch flat QD-OLED; 3840 × 2160; 0.1814 mm pixel pitch; anti-reflection surface

QD-OLED converts blue OLED light to red and green with quantum dots; because each pixel makes its own light, blacks can switch fully off. 4K at 32 inches gives roughly 140 ppi.

MSI
Resolution and pixel pitch2560 × 1440 (QHD); 0.2292 mm pixel pitch

QHD at 27 inches means lower pixel density than 4K; small text looks less crisp but high frame rates are easier to reach on the GPU.

LG		—
Refresh rate480 Hz

480 Hz means up to 480 frames per second; seeing that benefit requires the game and GPU to deliver close to 480 fps.

LG		—
Response time0.03 ms (GtG)

Grey-to-grey pixel transition time; it is not input lag.

LG		—
BrightnessTypical 275 cd/m² (min 250); HDR peak at 1.5% APL typical 1,300 cd/m² (min 1,040)

1,300 nits applies only to small highlights covering 1.5% of the screen; on a full white screen OLED automatic brightness limiting kicks in.

LG		—
Contrast1,500,000:1 (typical)

OLED pixels can switch fully off, so black level is near zero; LG’s page notes the figure is measured at 25% APL.

LG		—
ColourDCI-P3 98.5% (CIE 1976); 10-bit (1.07 billion colours)

The sheet lists a paper calibration report in the box.

LG		10-bit (1.07 billion colours); 99% DCI-P3, 97% Adobe RGB, 138% sRGB

138% sRGB means the gamut extends well beyond sRGB; use the monitor’s sRGB mode so sRGB content does not look oversaturated.

MSI
HDRHDR10; VESA DisplayHDR True Black 400

True Black is the VESA HDR tier for very low black-level displays such as OLED.

LG		—
Variable refreshVESA AdaptiveSync; NVIDIA G-SYNC Compatible; AMD FreeSync Premium Pro

Variable refresh matches the panel to the GPU frame rate to reduce tearing and stutter. LG’s page also lists VESA ClearMR 21000 certification.

LG		—
Screen surfaceAnti-glare, low-reflection front polariser LG—
Inputs2× HDMI (HDMI 2.1 FRL compliant); 1× DisplayPort 2.1

FRL is the high-bandwidth transfer mode of HDMI 2.1. There is no USB-C video input.

LG		1 × DisplayPort 1.4a; 2 × HDMI 2.1; 1 × USB-C (DP Alt Mode, 90 W PD); 2 × USB 2.0 Type-A, 1 × USB 2.0 Type-B; headphone out

The USB-C input can carry video and charge a laptop at up to 90 W over a single cable. Display Ninja says the monitor has a built-in KVM; the USB-A ports run at USB 2.0 speed.

MSI
USB and audioUSB 3.0: 1 upstream, 2 downstream; 4-pole headphone out (sound + mic); DTS Headphone:X

No built-in speakers are listed.

LG		—
StandTilt -5°/15°; swivel -30°/30°; height 110 mm; clockwise pivot; VESA 100 × 100

It has a tool-free 1Click stand mount and hexagonal RGB lighting on the back.

LG		—
PowerExternal adapter, 100–240 V; under 0.5 W in sleep, under 0.3 W off

The sheet does not list typical power consumption.

LG		—
Burn-in careOLED Care

LG says the feature helps prevent burn-in from static high-contrast images left on screen for long periods but may not prevent all image retention.

LG		—
Size and weightWith stand 23.8 × 22.8 × 9.8 in (raised), 20.5 lb; without stand 23.8 × 13.8 × 1.8 in, 11.2 lb

About 9.3 kg with stand, about 5.1 kg without.

LG		With stand 718 × 242 × 483 mm; without stand 718 × 69 × 418 mm; 9.6 kg net MSI
In the boxPower cord, DisplayPort 2.1 cable, HDMI 2.1 cable, USB A-to-B cable, paper calibration report LG—
Refresh and response—240 Hz (48–240 Hz variable range); 0.03 ms GtG

MSI says 240 Hz at 4K is reachable over DisplayPort 1.4a, HDMI 2.1 and USB-C alike. 0.03 ms is grey-to-grey transition time, not total input lag.

MSI
Brightness and HDR—250 nits typical; DisplayHDR True Black 400; 1,500,000:1 typical contrast

DisplayHDR True Black 400 is the VESA class for displays that can produce deep blacks such as OLED; it requires 400-nit small-area brightness and a very low black level. 250 nits is the full-screen SDR figure.

MSI
Adaptive sync—G-SYNC Compatible; AMD FreeSync Premium Pro

Adaptive sync matches the display refresh to the game’s frame rate to reduce tearing and stutter. FreeSync Premium Pro adds a low-latency requirement in HDR.

MSI
Stand and mounting—Tilt −5/15°, swivel ±30°, pivot ±10°, 110 mm height adjustment; VESA 100 × 100 MSI
Warranty—3 years, including panel burn-in

On OLED panels, images left static for long periods can leave a permanent mark (burn-in); MSI covers this risk under warranty. Terms may vary by country.

MSI